Hi, new here and I think this is an interesting thread
I learnt from a Mistress and was educated in domination but not how to be a Master. In fact I didn’t know she characterised her self as a mistress until much later on. I knew nothing of the life style; I was simply interested in what she had to teach and that lead to my being who I am and seeking to learn more. I believe any person, no matter what their interest, should seek to better their understanding and their approach, be it in Domination or the fly-fishing. (Not that I see those two crossing paths any time soon)

That definition doesn't have an age limit, but it does imply a certain level of ability and achievement
I could not agree more, the one thing I have noticed is there is a pre conceived notion that a Dom needs to be "older" though there is no one age that makes you a master. Now at 25 I still feel too young to be a Master and honestly feel i have much to learn before I start referring to my self that way. This however is a personal choice and not something i feel has been forced on me. I feel I need to learn more and believe I have come to the right place.